I wonder. You do find that in ATC a lot of rules/procedures/best practices come about from an incident or two!
AS for the CAA - well - don't know if they would agree! Arguably, unit management, through unit Assessors/Local Competency Examiners (who give us annual practical/theory exams) should highlight an unsafe practice.
Interestingly, thoughts such as "Freedom of Flight" become involved. It could be argued by some that refusing a transit if no traffic prevented it, would be unfairly restrictive!
The bottom line with it, is that it will depend on the pilot, his understanding of "alight clear" and ability. Oh yes, and opinions!!! Many factors would be taken into consideration in an incident so we will see.
Hopefully - it would never need to be tested.
Probably as much of a mention in the BUR-ASCOT route in the LCTR not above 1000' - even at night!
Anyone flown that at day or night and found it "interesting"?
Funnily enough, an ATCO from LHR had a rough running engine just North of Ascot last year in daytime. Managed to put the aircraft (a C152) down on the polo pitch. Fortunately the horses and riders cleared off in time!!! Aren't there any suitable sports pitches in the Lea Valley???